A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. including part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at once, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
In a substrate table and/or patterning device support of current lithographic apparatus, a so-called short stroke part may be dynamically coupled to a so-called long stroke part thereof by hoses and wires to transport, for example, a cooling medium and electrical power. The stiffness and damping of the hoses and wires between the short stroke part and the long stroke part act as a parasite and may cause position errors. This may have a negative influence on the general performance of the apparatus. In particular, the parasitic stiffness and damping of the hoses and wires may be:
1. inhomogeneous for different directions (x,y,z);
2. variable in time due to changing material properties due to heating; and
3. relatively large in magnitude, causing relatively large errors.
Due to the first two reasons, feed forward compensation of disturbance forces due to the parasitic stiffness and damping may only be possible to a small extent (especially damping), leaving a large disturbance error. In addition, this error is direction dependent. By using two-dimensionally preformed hoses and wires with small diameter and applying highly elastic materials, this effect may be reduced. However, demands on the lithographic process are growing and further improvements are desired.